package com.seckill.service.impl;

import com.seckill.dao.SeckillDao;
import com.seckill.dao.SuccessKilledDao;
import com.seckill.dto.Exposer;
import com.seckill.dto.SeckillExecution;
import com.seckill.entity.Seckill;
import com.seckill.entity.SuccessKilled;
import com.seckill.enums.SeckillStateEnum;
import com.seckill.exception.RepeatKillException;
import com.seckill.exception.SeckillCloseException;
import com.seckill.exception.SeckillException;
import com.seckill.service.SeckillService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.DigestUtils;

import java.util.Date;
import java.util.List;

//@Component表示代表所有组件 @Service @Dao @Controller
@Service
public class SeckillServiceImpl implements SeckillService {

    private Logger logger = LoggerFactory.getLogger(this.getClass());

    //注入Service
    @Autowired
    private SeckillDao seckillDao;

    @Autowired
    private SuccessKilledDao successKilledDao;

    //md5盐值字符串，用于混淆md5
    private final String slat = "jshdkja^*&*#$#fdsa154dfdsgf3134";

    @Override
    public List<Seckill> getSeckillList() {
        return seckillDao.queryAll(0,10);
    }

    @Override
    public Seckill getById(long seckillId) {
        return seckillDao.queryById(seckillId);
    }

    @Override
    public Exposer exportSeckillUrl(long seckillId) {
        Seckill seckill = seckillDao.queryById(seckillId);
        if (seckill == null){
            return new Exposer(false, seckillId);
        }
        Date startTime = seckill.getStartTime();
        Date endTime = seckill.getEndTime();
        //系统当前时间
        Date nowTime = new Date();
/*      System.out.println("startTime = " + startTime + "***" + startTime.getTime());
        System.out.println("nowTime = " + nowTime + "***" + nowTime.getTime());
        System.out.println("endTime = " + endTime + "***" + endTime.getTime());*/
        //秒杀未开始或者已结束
        if (nowTime.getTime() < startTime.getTime()
                || nowTime.getTime() > endTime.getTime()){
            //System.out.println("********");
            return new Exposer(false, seckillId, nowTime.getTime(), startTime.getTime(),
                    endTime.getTime());
        }
        //转化特定字符串的过程,不可逆
        String md5 = getMd5(seckillId);
        return new Exposer(true, md5, seckillId);
    }

    //生成md5
    private String getMd5(long seckillId){
        String base = seckillId + "/" + slat;
        String md5 = DigestUtils.md5DigestAsHex(base.getBytes());
        return md5;
    }

    @Override
    @Transactional
    /**
     * 使用注解控制事务方法的优点
     * 1：开发团队达成一致约定，明确标注事务方法的编程风格
     * 2：保证事务方法的执行时间尽可能短，不要穿插其他的网络操作，RPC/HTTP请求或者剥离到事务方法外
     * 3：不是所有的方法都需要事务，如只有一条修改操作，只读操作不需要事务控制
     */
    public SeckillExecution executeSeckill(long seckillId, long userPhone, String md5) throws SeckillException, RepeatKillException, SeckillCloseException {
        if(md5 == null || !md5.equals(getMd5(seckillId))){
            throw new SeckillException("seckill data rewrite");
        }
        //执行秒杀逻辑：减库存 + 记录购买行为
        Date nowTime = new Date();
        //减库存
        int updateCount = seckillDao.reduceNumber(seckillId, nowTime);

        try {
            if (updateCount <= 0){
                //没有更新到记录
                throw new SeckillCloseException("seckill is closed");
            }else {
                //记录购买行为
                int insertCount = successKilledDao.insertSuccessKilled(seckillId, userPhone);
                //唯一：seckillId，userPhone
                if (insertCount <= 0){
                    //重复秒杀
                    throw new RepeatKillException("seckill repeated");
                }else {
                    //秒杀成功
                    SuccessKilled successKilled = successKilledDao.queryByIdWithSeckill(seckillId, userPhone);
                    return new SeckillExecution(seckillId, SeckillStateEnum.SUCCESS, successKilled);
                }
            }
        } catch (SeckillCloseException e1){
            throw e1;
        } catch (RepeatKillException e2){
            throw e2;
        } catch (Exception e){
            logger.error(e.getMessage(), e);
            //所有编译期异常，转化为运行期异常（事务回滚）
            throw new SeckillException("seckill inner error" + e.getMessage());
        }
    }

}
